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Oct., 28, 2011 (Orlando, Fla.) -- People with Alzheimer's disease should have regular eye tests to screen for vision problems.

That's the recommendation of researchers who found that people with mild Alzheimer's disease who have cataracts may benefit from vision-correcting surgery. The benefits include improved sight, better sleep, and less depressed mood.

Also, people with Alzheimer's often had better communication and interaction with others after the surgery.

According to Brigitte Girard, MD, a professor of ophthalmology at Tenon Hospital in Paris, treatment improved the patients' lives and also the lives of some caregivers.

Girard reported the researchers' findings at the annual meeting of the American Academy of Ophthalmology (AAO) at the end of October.

Despite fears to the contrary, Girard says, surgery did not worsen patients' general condition or dementia.

William Thies, PhD, scientific director of the Alzheimer's Association, reviewed the findings for WebMD. He says that general medical care, including vision problems, are often overlooked in people with Alzheimer's.

"The assumption is made they won't benefit," Thies says. The assumption, he adds, is wrong. "The fact that they do benefit is very much the message from this study."

Improvements in Mood and Sleep

More than 1.5 million cataract surgeries are performed annually in the U.S. One in three Americans, most of them older people, will have the surgery at some point in their life.

The surgery is performed to remove the natural lens of the eye, which sometimes becomes clouded over time. A permanent artificial lens is then implanted to replace the natural lens.

The study involved 38 people with mild Alzheimer's disease who underwent cataract surgery. The average age was 86; nine were 90 or older. The majority (82%) were women.

Three months after surgery, all but one patient could see better. Three in four patients had improved or unchanged scores on tests of mood, memory, and their ability to wash, dress, and otherwise function independently. Sleep, in particular, improved, Girard says.

Six of the seven people with depression before surgery were less depressed afterward. The other person's depression was about the same as before.

As rated by the patients and their caregivers, social lives improved or were unchanged in two out of every three people studied.

Girard says "unchanged" scores were considered a mark of success. "As one neurologist told me," she says, "if people with Alzheimer's disease don't get worse over three months, it's a win."

The researchers did find that some people were more agitated after the surgery.

Benefits for Caregivers

The study also found that the surgery eased the burden for one in four caregivers. For another one in four, though, caring for their loved one was harder. The main reason cited was an increased level of agitation.

Thies points out that the study was small and there was no comparison group that did not get surgery to compare the results to.

Still, he tells WebMD, there are a lot of things that can contribute to a person's sensory deprivation. "If you can improve those things," he says, "you will improve their ability to perform."

AAO spokesman Jeffrey Whitman, MD, of the Key-Whitman Eye Center in Dallas, says, "I find this study to be a proof of what we may have already suspected -- that poor vision, in an already compromised patient, is a burden to both the patient and the patient's caretaker."

In an email, Whitman, who is the son of an Alzheimer's patient, told WebMD: "I have found that anything that can help mobility, the ability to feed oneself, or ambulate from room to room, is a great boon."

He adds that better vision leads to better nighttime behavior. A person with Alzheimer's often displays what's known as sun-downing behavior, in which forgetfulness and other symptoms worsen at dusk.

In addition, better vision can lead to less depression among people that uniformly become more depressed as the disease advances. "The continued evaluation and surgical management of cataracts should be pursued in these often forgotten patients," Whitman says.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.